Ho-Kyung Kwak

Flavonoid-Rich Dark Chocolate Improves Endothelial Function and Increases Plasma Epicatechin Concentrations in Healthy Adults

Background: Dark chocolate derived from the plant (Theobroma cacao) is a rich source of flavonoids. Cardioprotective effects including antioxidant properties, inhibition of platelet activity, and activation of endothelial nitric oxide synthase have been ascribed to the cocoa flavonoids. Objective: To investigate the effects of flavonoid-rich dark chocolate on endothelial function, measures of oxidative stress, blood lipids, and blood pressure in healthy adult subjects. Design: The study was a randomized, double-blind, placebo-controlled design conducted over a 2 week period in 21 healthy adult subjects. Subjects were randomly assigned to daily intake of high-flavonoid (213 mg procyanidins, 46 mg epicatechin) or low-flavonoid dark chocolate bars (46 g, 1.6 oz). Results: High-flavonoid chocolate consumption improved endothelium-dependent flow-mediated dilation (FMD) of the brachial artery (mean change = 1.3 ± 0.7%) as compared to low-flavonoid chocolate consumption (mean change = −0.96 ± 0.5%) (p = 0.024). No significant differences were noted in the resistance to LDL oxidation, total antioxidant capacity, 8-isoprostanes, blood pressure, lipid parameters, body weight or body mass index (BMI) between the two groups. Plasma epicatechin concentrations were markedly increased at 2 weeks in the high-flavonoid group (204.4 ± 18.5 nmol/L, p ≤ 0.001) but not in the low-flavonoid group (17.5 ± 9 nmol/L, p = 0.99). Conclusion: Flavonoid-rich dark chocolate improves endothelial function and is associated with an increase in plasma epicatechin concentrations in healthy adults. No changes in oxidative stress measures, lipid profiles, blood pressure, body weight or BMI were seen.

Effects of freeze-dried cranberry powder on serum lipids and inflammatory markers in lipopolysaccharide treated rats fed an atherogenic diet

This study investigated the effects of freeze-dried cranberry powder on anti-inflammation and lipid profiles of lipopolysaccharide (LPS)-treated rats fed an atherogenic diet for 6 weeks. Forty Sprague-Dawley male rats (6-weeks-old) were equally divided into the following five groups: 1) normal diet group + saline (NC); 2) atherogenic diet + saline (HFC); 3) atherogenic diet + LPS (HL); 4) atherogenic diet with 5% cranberry power + LPS (C5); 5) atherogenic diet with 10% cranberry power + LPS (C10). LPS (0.5 mg/kg) was injected into the abdominal cavities of rats 18 hours prior to sacrifice. At the end of the experimental period, we measured serum lipid profiles as well as levels of serum C-reactive protein (CRP), nitric oxide (NO), and pro-inflammatory cytokines such as tumor necrosis factor-α (TNF-α), interleukin (IL)-1β, IL-6, and IL-10 as an anti-inflammatory cytokine. The mean serum high density lipoprotein (HDL)-cholesterol level in C5 rats was significantly higher than that in NC and HL rats (P < 0.05). The mean serum levels of CRP and IL-1β were significantly lower (P < 0.05) in the cranberry powder groups compared to those in HL rats. Additionally, mean serum IL-6 levels tended to be lower in the cranberry groups than that in the HL group, whereas serum IL-10 and NO showed 29% and 88% higher mean values in the C5 group and 49% and 24% higher in the C10 group than those in the HL group, respectively. These results suggest that freeze-dried cranberry powder may have beneficial effects on cardiovascular diseases by modifying serum lipids and the early inflammatory response.

The effects of A. senticosus supplementation on serum lipid profiles, biomarkers of oxidative stress, and lymphocyte DNA damage in postmenopausal women

This study examined the effects of Acanthopanax senticosus supplementation on serum lipid profiles, biomarkers of oxidative stress, and lymphocyte DNA damage in postmenopausal women. Forty postmenopausal women, ages 40-65, were randomly divided into two groups: (1) control group (calcium) and (2) treatment group (calcium plus A. senticosus). Both groups were treated for 6 months. Blood samples were obtained before and after supplementation at 6 months. The following blood parameters were measured: serum total cholesterol, triglycerides (TG), low-density lipoprotein (LDL), high-density lipoprotein (HDL), serum malondialdehyde (MDA), ccdd protein-carbonyl (PC) levels, the degree of lymphocyte DNA damage by comet assay, total ferric reducing antioxidant power (FRAP), uric acid, and total bilirubin in serum. The treatment group had significant decreases (p<0.001) in serum LDL (127.54+/-29.79mg/dL vs 110.33+/-22.26mg/dL) and the LDL/HDL ratio (2.40+/-0.65 vs 2.11+/-0.58) after A. senticosus supplementation. Serum MDA concentrations decreased by 2.2% in the control group and by 12.61% in the treatment group after 6 months of intervention; however, the reductions were not significant in either group. Protein-carbonyl levels and lymphocyte DNA damage decreased significantly (p<0.001 and p<0.05, respectively) after 6 months of A. senticosus supplementation. These results suggest that A. senticosus supplementation may have beneficial effects against oxidative stress and improve serum lipid profiles without subsequent side effects.

Antioxidant and antiinflammatory activities of cyanidin-3-glucoside and cyanidin-3-rutinoside in hydrogen peroxide and lipopolysaccharide-treated RAW264.7 cells

Cyanidin-3-glucoside (C3G) and cyanidin-3-rutinoside (C3R) are 2 major anthocyanins found in Korean Rubus fruits (blackberries, raspberries, and black raspberries). The antioxidant and antiinflammatory effects of C3G and C3R in RAW264.7 murine macrophage cells were determined. Anthocyanins (5, 10, and 20 μg/mL) significantly (p<0.05) reduced H2O2-induced cytotoxicity in H2O2-stimulated RAW264.7 cells, compared with control cells. Incubation with C3G or C3R significantly (p<0.05) decreased intracellular reactive oxygen species and DNA damage (Hoechst and comet assay), and the cellular ferric reducing antioxidant power also increased, compared with control cells. Nitric oxide production in LPS-stimulated RAW264.7 cells treated with C3G and C3R was reduced by 41.9 and 34.4%, respectively. In addition, LPS-induced prostaglandin E2 production was significantly (p<0.05) inhibited by C3G (51.7%) and C3R (58.6%), compared with LPS-stimulated control cells. Protein expressions of iNOS and COX-2 decreased in cells treated with anthocyanins. Anthocyanins down-regulated NF-κB expression and up-regulated I-κB expression in LPS-treated macrophages.

Effects of cranberry powder on biomarkers of oxidative stress and glucose control in db/db mice

Increased oxidative stress in obese diabetes may have causal effects on diabetic complications, including dyslipidemia. Lipopolysccharides (LPS) along with an atherogenic diet have been found to increase oxidative stress and insulin resistance. Cranberry has been recognized as having beneficial effects on diseases related to oxidative stress. Therefore, we employed obese diabetic animals treated with an atherogenic diet and LPS, with the aim of examining the effects of cranberry powder (CP) on diabetic related metabolic conditions, including lipid profiles, serum insulin and glucose, and biomarkers of oxidative stress. Forty C57BL/KsJ-db/db mice were divided into the following five groups: normal diet + saline, atherogenic diet + saline, atherogenic diet + LPS, atherogenic diet + 5% CP + LPS, and atherogenic diet + 10% CP + LPS. Consumption of an atherogenic diet resulted in elevation of serum total cholesterol and atherogenic index (AI) and reduction of high density lipoprotein (HDL)-cholesterol. However, with 10% CP, the increase in mean HDL-cholesterol level was close to that of the group with a normal diet, whereas AI was maintained at a higher level than that of the group with a normal diet. LPS induced elevated serum insulin level was lowered by greater than 60% with CP (P < 0.05), and mean serum glucose level was reduced by approximately 19% with 5% CP (P > 0.05). Mean activity of liver cytosolic glutathione peroxidase was significantly increased by LPS injection, however it was reduced back to the value without LPS when the diet was fortified with 10% CP (P < 0.05). In groups with CP, a reduction in mean levels of serum protein carbonyl tended to occur in a dose dependent manner. Particularly with 10% CP, a reduction of approximately 89% was observed (P > 0.05). Overall results suggest that fortification of the atherogenic diet with CP may have potential health benefits for obese diabetes with high oxidative stress, by modulation of physical conditions, including some biomarkers of oxidative stress.

Relation of serum total antioxidant status with metabolic risk factors in Korean adults

The purpose of the present study was to examine the relation of total antioxidant status (TAS) to metabolic risk factors in Korean adults. Anthropometric measures, blood pressure, serum lipids and fasting glucose were determined in 406 men and women. TAS was measured by using commercially available Randox kit. Serum TAS was significantly positively correlated with body weight (p=0.004), body mass index (BMI) (p=0.033), waist circumference (p=0.017), total cholesterol (p=0.038) and triglyceride (TG) (p<0.001). The mean TAS of hypertriglyceridemic subjects (TG ≥150 mg/dl) was significantly higher than that of subjects whose TG was lower than 150 mg/dl (p=0.001). When central obesity, TG, high density lipoprotein cholesterol, fasting glucose and blood pressure were considered as metabolic risk factors, TAS was shown to be elevated with increased number of metabolic risk factors (p=0.004). The positive association between TAS and a number of metabolic risk factors suggests that increased TAS may not always indicate ones healthier condition. In order to help understand TAS as a marker of total antioxidant capacity in humans with various metabolic conditions, it is needed to clarify the factors affecting TAS in relation to changes in metabolic risk factors.

Antioxidant Effects of Cranberry Powder in Lipopolysaccharide Treated Hypercholesterolemic Rats

This study was conducted to investigate the effects of cranberry power on antioxidant defense system in rats fed an atherogenic diet and injected with lipopolysaccharide (LPS). Sprague-Dawley rats were divided into the following 5 groups: normal diet+saline (NS), atherogenic diet+saline (AS), atherogenic diet+LPS (AL), atherogenic diet with 5% cranberry powder+LPS (AL-C5), and atherogenic diet with 10% cranberry powder+LPS (AL-C10). Total antioxidant status measured by ferric reducing ability of plasma (FRAP) was significantly reduced by LPS injection (24%) and was restored by the cranberry powder treatment (P<0.05). In addition, the mean level of plasma total phenolics was significantly decreased by LPS injection (P<0.05) and tended to be increased when cranberry powder was incorporated in to the diet. Activity of serum superoxide dismutase (SOD) tended to be lowered by LPS injection and declined further in cranberry powder fortified groups. Overall results indicate that dietary cranberry powder may provide appropriate antioxidants to counter the diminished antioxidant status induced by exposing hypercholesterolemic rats to LPS.

Anthocyanins in Rubus fruits and antioxidant and anti-inflammatory activities in RAW 264.7 cells

Antioxidant and anti-inflammatory activities of ethanol extracts (E) and anthocyanin fractions (AF) from the 3 Rubus fruits blackberries, Korean raspberries, and black raspberries (BR) produced in Korea were determined. BR contained the highest levels of total polyphenols, flavonoids, anthocyanins, and the highest antioxidant activity. E and AF protected RAW 264.7 cells against H2O2-induced cytotoxicity. AF at 20 µg/mL significantly (p<0.05) decreased intracellular ROS levels (39.1-43.5%) and increased SOD (7.1-35.9%) and GPx (7.5-48.6%) activities in H2O2-treated RAW 264.7 cells, compared with controls. AF also increased Nrf2 protein expression. All AF significantly (p<0.05) reduced H2O2-induced DNA oxidation, compared with controls. AF suppressed NO (32.4-42.9%) and PGE2 (17.4-49.0%) production in LPS-stimulated RAW 264.7 cells along with a decrease in LPS-induced iNOS and COX-2 protein expressions. AF significantly (p<0.05) down-regulated NF-κB expression, compared with controls, via inhibition of I-κBα degradation in LPS-stimulated RAW 264.7 cells.